Defibrillators are typically portable units that are used in Emergency Resuscitation. When a patient experiences sudden cardiac arrest (not moving), the unit will provide an electric shock to be transferred to their heart. Most units will run off an automatic programme. The electricity is carried via insulated cables from a safe distance, isolating it from contact. This verifies that the charge is only travelling to where the unit is connected to, and nowhere else.

The user will turn the device on, connect the shock pads, and listen to any vocal instructions issued by it. The prompts will involve providing compressions (and breaths), electric shocks, and waiting. The unit needs time to read the patient’s heart and charge the capacitor.